Each type of crude oil has unique molecular characteristics. These characteristics include different physical and chemical properties that can potentially affect the refining process. Typically, crude oils contain trace amounts of metal, such as vanadium or nickel. These metals become concentrated in the residual fractions of the refining process and can contaminate the products, poison catalysts, or corrode equipment. Refineries, therefore, seek to remove these metals prior to, or during, the refining process. Before a metal can be removed from crude oil, however, the refineries must identify the characteristics of the crude oil, including which metals are present and their concentrations. To do so, refineries can generate characterization data (or assay data) of a crude oil feedstock in a petroleum testing laboratory. Using the characterization (assay) data, refineries can estimate the characterization of a crude oil feedstock with respect to hydrocarbon content via a number of methods including use of a probability distribution function for hydrocarbon constituent molecules, as described in U.S. patent application Ser. No. 13/740,095 (submitted by Applicant), which is herein incorporated by reference in its entirety.
As global oil supply shifts towards heavy crude oils, refinery feeds will contain an increased amount of trace metals. Creation of efficient demetallation strategies will need an appropriate characterization to identify trace metals. A need for such characterization, therefore, exists.